The present invention is directed to an injection-molded article and method of manufacturing thereof and, in particular, to an injection-molded powdered metal-filled plastic member and method of manufacture thereof. While the invention is illustrated with manufacture of a permanent magnet molded over a form, such as a rotor of a brushless DC motor, it may apply to other types of bonded metal assemblies, such as electrical generators, electro-magnetic sensors, and the like.
It has long been known to manufacture powdered metal-filled plastic members, such as permanent magnets using injection-molding techniques. This is accomplished by injecting or shooting a molten or liquid powdered metal-filled plastic material into a hollow cavity, known as a mold, and allowing the material to cool to a point of solidification or otherwise curing the material.